Mold for casting of pipes of cementitious material



Dec. 4, 1934.

E. H. BISHOP 983,117

MOLD FOR CASTING OF PIPES OF CEMENTITIOUS MATERIAL Filed Jan. 22, 1932 Edward PATENT OFFICE MOLD FOR CASTING. F PIPES 0F CEMENTITIOUS MATERIAL Henry Bishop, Waverley, near Sydney,

New South Wales, Australia Application January 22, 1932, Serial No. 588,057 In Australia January 29, 1931 3 Claims. (01. 25-127) This invention has been devised to provide cheap, simple and effective mechanism for the casting of pipes of concrete or other cementitious material especially useful for the casting of concrete pipes in situ wherein complete package of the concrete forming the pipe is assured and e is easily effected and wherein voids and. bubbles and the like in the concrete forming the pipe are eliminated and which mechanism canbe quickly .assembled andquickly and easily removed from a pipe when formed.

According to this invention the mechanism for casting pipesin a present preferred construction consists of a core in two parts and a single semicover mold both of configuration conforming to the interior and exterior respectively of the desired pipe which pipe for the purpose of this description will beregarded as cylindrical. One half partofwthe core is adapted to be superimposed on the'other and both parts are constructed of a plurality of longitudinal a-rcuate ,slats, say three, fast to divided semi-circular ribs having. hinges adjacent theYmeeting edges of said slatsso that the' outer slats are collapsible towards each other. Thefree ends of the hinged ribs in each half core are. connected by toggle struts having a common draw-bar pivoted thereto which retainjfltheslats of the half corerigidly in positionand enables the half core to beeasily collapsed to facilitate removal thereef. The cover is constituted of a pluralityof arcuateslats (say four) which are longitudinally hinged to a plurality of semi-circular frames. The slats on either side of the crown or top of the cover are adapted to, fold inwardly and so leave an orifice for package of concrete about the lower part of the top half of the core and the lowermost slats on either side of the cover are adapted to fold outwardly to facilitate removal of the cover from a a t p pe- For cores for large pipessay those over thirty inches in diameter rollers or trolleys to bear the .weight of the half cores are provided together withv devices to operate them during extraction .1.45 from a finished pip But inorder that this invention may be readily carried into. practical effect it will now be described with reference. to the drawing (which is .more or. less schematic) accompanying and formingpartof this complete specification. 1

is a fragmentary plan of a lower half core. Fig. 2is an end elevation ofa complete core. Fig. 3 is a fragmentary plan of a lower half core when collapsedfor extraction. Fig. *iis an end elevation of a complete core with the lower half collapsed. Fig. 5 is a fragmentary plan of a cover. Fig. 6 is an end elevation of a cover. and core and a pipe in the making. Fig. 7 is a sectional elevation of a lower half core withone form of removing mechanism therefor, whilst Fig. 8 is an end elevation of an upper half core in a pipe with one for'mof removing mechanism therefor.

The coreupper and lowerparts 9 and 10 are both constituted of a plurality of semi-circular ribsrll and 12 hinged as at 13 to enable the ribs 12 to be collapsed inwardly about said hinges l3. slats l4 and 15 are riveted or otherwise fast to said ribs 11 and 12 respectively and strengthening strips 16 are inset in said ribs at the meeting edges of the slats l4 and 15'. The free ends 1'? of each of the ribs 12 arejoined by a toggle strut 18 having interposed swivelling brackets 19 vertically hinged to said struts 18 as at 20 and hinged horizontally to the ribs 12 by hinges 21 thus constituting universal couplings for said struts. The toggle struts18 have a common knee 22 with opening stop 23 and the knees 22 are pivotally connected to a common pull rod 24. The cover is constituted of a plurality of semicircular frames 25 divided as at 26 and the divided ends 27 are. hinged to the main frame 25 by catches 32 to take over the edges of the slats. 31 If}? to retain said slats 29 in extended circular position whennecessary and the strap hinges 28 are hinged asiindicated at 33 to the frames 25 and have orifices juxtaposed studs 34 fast in the frames 25 and nuts 35' to retain said straps together with the slats 31 in closed circular position when in use.

The half cores 9 and 10 at one end are stepped as shown at 36 sothateach core can be laid overlapping or underlapping its preceding fellow and similarly the covers are provided with stepped ends 3'7 and 38 for the same reason and further the covers are provided with end plates 39 to enable each to be supported at one end by its preceding fellow. i

The casting of pipes according. to this invention whether in situ or in a factory is commenced by preparing a bed as 40 say with a simple semicircular-template of the same radius as the outside radius of the required pipe in the earth or other medium and the thus formed bed is then pared' say for example a length equivalent to the length of four cores (a convenient length for each core would be from six to eight feet) and the laying of paper is followed by the laying of suitable metal reinforcements if required. Distance blocks of concrete of the same thickness as the pipe when finished are made and set in the bed and whereon (when sufiiciently hardened) are rested the ends of the half cores 10 (which are weighted if necessary) with the slats 15 infolded as shown in Figs. 3 and 4. The first core laid is overlapped the end of the pipe source or nozzle from which the pipe is required to extend and a quantity of plastic concrete is then packed by tamping (or by other convenient means) under the half cores until the top level of the slats 14 is almost reached when the slats 15 are opened outwardly and retained in such position by the extended toggle struts 18 and the filling and tamping continued until the top level of the half core 10 and/or the bed is almost reached. The upper half cores 9 are then placed on the lower half cores with the slot edge of the former overlapping the strips 16 and concrete distance blocks made and set thereon with reinforcements if required laid therearound. The covers are then placed over the top half core and the slats 31 are rigidly clamped in position by the nuts 35 and the slats 29 are left loose (as shown in Fig. 6) to enable insertion and tamping of concrete until the top edges of the slats 31 are almost reached when the slats 29 are lifted and secured in semi-circular position by the catches 32 taking over the edge of the slats 31. The filling and tamping of concrete is then proceeded with through the opening between the slats 29 until the concrete is level with such opening.

It will be apparent that the several stages of the work can be carried out in rotation for example when the distance blocks are finished for a certain distance it will be found that those first made will have hardened suiiiciently to enable the lower half cores to be positioned at the initial end of the section and when the first filling and tamping operation is well under way the second filling and tamping operation can be commenced and so on right through the section being laid.

After the concrete has set sufficiently to allow removal of the cores the cover is removed by unscrewing the nuts 35 and releasing the catches 32 whereupon the slats 31 are rotatable away from the pipe about the hinges 33 and the cover is easily lifted off.

To extract the core the lower half 10 is first collapsed by hauling the pull rod 24 which being hinged to the knee 22 of the toggle strut 18 causes the slats 15 to be swung about hinges 13 until in the position shown in Figs. 3 and 4 when such lower half core can be easily extracted. The upper half core is collapsed and withdrawn in like manner to the lower half. Where the work is being carried out with a multiplicity of cores the tail end of each pull rod 24 may be loosely shackled to the leading end of the preceding pull rod so that when the first half core has been collapsed and moved and the loose coupling tautened the second pull rod is operated to collapse the second core part and so on all the cores in a section being withdrawn in a train.

If it be found that a complete train of half cores is too heavy to haul out of the pipe in one operation or is otherwise too difiicult to manipulate then each half core or gangs of two or more thereof has a hauling rope shackled to the leading end of the pull rod 24 and such ropes are passed through all the cores to the open end of the work when hauling thereon will collapse the cores in following sequence and withdraw same.

In the casting of large pipes (say those over thirty inches diameter) the cores become too weighty and unwieldy to be simply dragged out of the pipe and so the lower half core is furnished with a roller 42 on a lever 43 fulcrumed in a bearing 44 on the end rib 45 of a lower half core. The lever 43 has pivoted to it a second lever 46 which is fulcrumed as at 47 and when the lever 46 is depressed and caught under a hook such as 48 (Fig. 2) the half core is lifted clear (after having been collapsed) of the pipe floor at the roller end and said roller contacts the interior of the preceding core until extraction commences when it runs on the floor of the pipe. To lift the outer end of each lower half core a lever of the crowbar type having a roller in the heel thereof is provided as indicated at 49 and the toe of said lever is adapted to take under a loop such as 50 (Fig. 2) so that the half core is raised on the rollers at each end thereof and can easily be withdrawn.

The upper half core can be extracted by merely collapsing same onto the lower half core and withdrawing same together but preferably the lower half of the pipe is completed first and the lower half cores removed and the upper half cores separately placed in position. Each of said upper half cores are mounted on two or more standards 51 consisting of frames 52 riveted to said upper half core as at 53 and having bottom roller 54 and side rollers 55 on a cross bar 56. The standards 51 are spaced apart as shown to enable the pull rod 24 to pass therebetween.

The upper cores are extracted by first collapsing the slats 15 when the upper half core drops until the rollers 54 and. 55 contact the floor of the pipe when the half cores can easily be extracted either singly or in gangs as aforesaid.

Where concrete pipes having bituminous linings are required the bitumen is treated in like manner to the concrete except that an additional lower half core and. an additional cover are required. The lower concrete half of the pipe is first cast as described above but by using the additional lower half core which is greater in diameter than the core proper in accordance with the thickness of bitumen lining required. The bitumen lining is then cast using the core proper and the additional cover which is the same diameter as the additional lower half core and the upper half of the concrete pipe cast on the bitumen lining shell using the full sized cover as hereinbefore described.

Although particular constructions of mechanism to carry this invention into practical effect have been described and illustrated herein it is to be clearly understood that applicant is not confined to such precise constructions for many variations thereof will be readily conceived by those skilled in the art to which this invention appertains. For example the core may be in one piece consisting of a plurality of slats which are collapsible by other means than toggle levers and pull rods. In one such construction each slat forms a true segment of the core. Each slat has one edge termed a lead in edge linked to a part revolvable boss and the other edge of each slat has a stub in a spiral guide. On turning the boss in one direction the link pulls the lead in edge in a spiral track towards the center under the next leading slat while rear edge of the slat trav- 1,983,117 elling in its guide is travelled inwardly and so plying to the casting of pipes it may equally as well be employed for the casting of linings in existing pipes.

1. The combination of a pipe casing core comprising two separable parts, each made up of a central rigid portion having arcuate transverse ribs thereon, and side portions having arcuate transverse ribs thereon, said side portion ribs being respectively hinged to the ribs of said central rigid portion; toggle struts for each separable core part, each made up of two bars having a common central knee pivotally connected to a common pull-rod; lugs hinged to the ends of said bars and to the free ends of said side portion ribs; and a semicover mold comprising a body open centrally at the top, inwardly swinging wall sections at each side of said opening, and outwardly swinging wall sections at the lower side edges of said cover.

2. The combination of a pipe casing core comprising two separable parts, each made up of a central rigid portion having arcuate transverse ribs thereon, and side portions having arcuate transverse ribs thereon, said side portion ribs being respectively hinged to the ribs of said central rigid portion; toggle struts for each separable core part, each made up of two bars having a common central knee pivotally connected to a common'pull-rod; lugs hinged to the ends of said bars and to the free ends of said side portion ribs; and a semicover mold made up of arcuate transverse frames comprising a central fixed portion and two side portions hinged to said fixed portions, a pair of longitudinal top slats hinged to said fixed portions having a space therebetween, longitudinal side slats aflixed to said side portions and catches to hold said fixed slats and said hinged slats in edge to edge contact.

3. The combination of a pipe casing core comprising two separable parts, each made up of a central rigid portion having arcuate transverse ribs thereon and side portions having arcuate transverse ribs thereon, said side portion ribs being respectively hinged to the ribs of said central rigid portion; toggle struts for each separable core part, each made up off two bars having a common central knee pivotally connected to a common pull-rod; lugs hinged to the ends of said bars and to the free ends of said side portion ribs; carriage mechanism for the upper part of said core comprising standards afiixed to the central rigid portion of said core part, having a roller at the bottom thereof and cross bars on said standards having side rollers thereon; carriage mechanism for the lower part of said core comprising a roller on a bent lever fulcrumed on one of the end ribs of said central rigid portion; a hand lever pivoted to said bent lever and fulcrumed onanother of the ribs of said central rigid portion; a hook to maintain said hand lever in depressed position; a drag lever operatively engaging said core and having a roller at its fulcrum; and a semicover mold comprising a body open centrally at the top, inwardly swinging wall sections at each side of said opening, and outwardly swinging wall sections at the lower side edges of said cover.

EDWARD HENRY BISHOP. 

